IMPHAL, India (Reuters) - Thrown face down in an open drain by a grenade blast, Maisnam Ratan's bloodied corpse was the latest reminder of the lingering insurgency in Manipur, which elects a state legislature on Saturday. Manipur, which neighbours Myanmar, is called the Jewel of India for its paddy fields, lakes and green hills. But it has been plagued for decades by a low-intensity war, blamed by authorities on rebels sheltering in Myanmar as well as a stream of drugs and guns seeping through the porous border. ...